Ellipsograph



Dec. 22, 1931. R. E. MANN ELLIPSOGRAPH Filed Ju1y- 11, 1929 2 Sheets-Sheet Dec. 22, 1931. R E MANN 1,837,912

ELLIPSOGRAPH Filed July 11, 1929 2 Sheets-Sheet 2 lilllll may be also adapted Patented Dec. 22, 1931 .srATEs ROBERT E. MANN, F VENICE, CALIFORNIA ELLIPSOGRAPH Application filed July 11, 1929. Serial No. 377,552.

My invention is an improvement in geometrical instruments and relates more especially to devices" of this nature for the purpose of describing an ellipse andknown as 'ellipsographs.

The primary object of my invention is to provide a mechanical device or improved trammel for the purpose of drawing ellipses of various dimensions and contemplating an arrangement of the parts whereby the device different diameters.

A further object of my invention is to provide a mechanical device of this general character which can be easily and conveniently manipulated in connection with either pencil or pen and a wide range of adjustments made for drawing ellipses of small and large diameters without requiring a trammel frame of large dimensions, and including an attachment for the pen or pencil usable in connection with both rods and a bearing block traveling on-the rim of the frame for use in connection with the device when used for drawing circles.

With these principal objects in view my invention consists in the particular construction of the parts including a frame having a circular rim and crossed slots therebetween with shiftable supporting legs for said frame,

together with blocks slidable in the slots with respect to one another and rods of different lengths attachable to said blocks above and below the frame for carrying the scriber, one of the blocks being provided with a swivelled cap for adapting the device in drawing circles; all as hereinafter fully described and particularly set forth in the appended claims.

In the drawings Figure l is a perspective view of my improved mechanical device for drawing ellipses and circles. v

Fig. 2 is a top plan view of the device.

Fig. 3 is a side elevation.

Fig. 4 is a transverse sectional view on a line with one of the diametral slots.

Fig. 5 is a detail sectional view of one of the blocks adapting the device for drawing circles.

for drawing circles of,

Fig. 6 is a similar view of the companion block, and

Fig. 7 is a detail view of the holder for connecting the scriber to either one of the rods.

Like numerals of reference indicate like parts in the several views of the drawings.

In carrying out my invention the main frame of the device is similar to that of an ordinary trammel and consists of a circular f-t which cross each other at the center of the frame, and for supporting the frame at the desired height above the drawing board three legs 14 are employed in the present instance and connected to the rim by set screws 15 and 16 (Fig. 3) the set screw 15 passing through r.

the rim from above into the offset portion of the leg at the underside of the rim while the screw 16 extends upwardly through said offset portion into the rim whereby the legs may be disposed at any required angle with respect to the frame in the operation of the device as hereinafter explained, and more rigidly secured by screw 16 when disposed radially. The lower ends of the legs are turned outwardly to form feet 17 the device in place on the drawing board a pointed screw 18 is threaded through each foot, said screws also providing for adjusting the height of the frame.

For drawing ellipses blocks 19 and 20 are slidable in the respective slots and provided in the upper part thereof withtransverse apertures or openings, 19a20a, through which a rod 21 passes from one to the other of said blocks and carries a scribereither pencil or penfor drawing large ellipses, said blocks being also extended below the frame to receive an additional rod 22 for drawing small ellipses within the zone of the supporting legs, the rod 22 passing through transverse apertures 19?) and 20b in the blocks. By reference to Fi s. 5 and 6 it will be seen that these blocks are made in two parts or members for connection to the frame, one

and for holding of said members being provided with a rec tangular projection 23 extending through the rotatably connected to the block by means of a peripherally grooved stem 29 extending into said block and engaged by a set' screw (see Fig- 5). Rod 21 extending through the upper portions of the blocks 19 and 20 is. adjustably. connected thereto by set screws 31 and 32 (Fig. 1) and rod 22. which extends through, the lower portionsof. said blocks is likewise adjustably connected by set screw 33. threaded in block19 and knurled nut 84 threaded on the rod against the outer side of block 20.

It will be. understood that when a small ellipse isbeing drawn within the supporting legs by the use.-.of. rod 22 the other rod 21 is used as the operating lever, but when the longer rod. is being used for drawing ellipses beyond the supporting frame rod 22 may be removed, and in drawing ellipses of such a size, that thelegs in normal position (Fig. 1) would interferesaid legs may be shifted, as indicated in dotted lines Fig. 2, in. which case the longer rod of course will be used; consequently ellipses of various sizes as to longitudinal and transverse diameters may be drawn by simply adjusting the blocks with respect to each other, as for instance the distancebetween block 19 and the scriber is set tioequal theradius of the minor diameter of theellipse and the distance between block 20 and the scriber is set to equal the radius of themajor diameter, and should it be desired toidraw two ellipses-across each other at'right angles this is accomplished by placing a scriber on each projecting end portion of the rod being used and sliding the rod through so that the pencil points are at the same distance from blocks 19 and 20 at each end, as will, be obvious. Furthermore, when the device is used for drawing circles block .19is positioned at the center of the frame and held in place by rod 22 (Fig. 4-) which'is passed through the block' 19 and through block 20 at one side and througha similar block 85 at the other side, said supplemental block. being secured to the rod by a set screw 36 whileknurlednut 84 is threaded against the opposite block 20, whereby a fixed fulcrum for the rod: 21. is provided so that the scriber carried by said rod may be manipulated in describing acircle. Rod 21is graduated for the accurate spacing of the blocks andscriberswith respect to the longitudinal and transverse diameters of the ellipses, and of course rod 22 may be also graduated.

Any preferred form of scriber or drawing instrument may be used, as pencil 37 or pen 38, and for convenience in connecting the scriber to either of said rods I employ a holder 39 consisting of a member having a longitudinal opening 40 (Fig. 7) at one end and a transverse opening 41 at the other end to receive a rod and drawing instrument according to theme of said holder with respect to said rods-the rod 22 being passed through the longitudinal opening and the shank of the drawing instrument through the other in one instance (Fig; 3) and the positions reversed in the other instance or whenthe holder is usedinconnection withrod 21 (Fig. 4) with set screws, 42 and 43 for connectingthe holder to the respective parts; this holder thereby compensating for the distance of said rods from the drawing board. respectively for use in connection with the drawing instruments. Howevena modified, form ofvholder 44 may be used, in connect-ion with rod 21 as shown inFig. 1 of thedrawings and connected thereto by set screw 45, and in order to steady the rod 21 in describing a circle ablock 46 is adjustable o-nsaidrod by set. screw 47 and provided with a ball'bearing- 48 at its lower end adapted to travel around the rim of the frame, asshown in Fig. 4.

From thev foregoingdescription in connection with the accompanying drawings the construction and operation of my improved device for drawing ellipses and circles will be readily understood, the rods being, guided by the blocks traveling in the crossed slots after themanner of atrammehin the present instance the shorter rod 22 being used for small ellipses within the zone of the legs and the longer rod 21 for drawing ellipses beyond the zone of the legs, the latter being shifted so asto not interfere with ellipses in the intermediate zone, and for drawing circles the blocks 19, 20,.and35 are connected so that the block 19 will be held at the center of the frame with the attachment 46 adjusted so that, the ballbearing at the lower end thereof will travel around the circular rim of said frame, it being understood that for the purpose of drawing smaller circles with the rod 22'bl'ock 19 can bereversed and intermediate circles drawn. by shifting the legs as explained with reference to drawing ellipses.

The device is light in construction and provides simple and effective means for accurately drawing true ellipses of any desired size as to longitudinal and transverse diameters, the holder which is used in connection with the rods permitting the use of pen or pencil of the kind used in connection with other mechanical instruments, as compasses, etc., it being understood that the form of blocks and cooperating attachments herein shown and described may be varied in detail and other modifications resorted to in carrying out my invention within the spirit and scope of the claims.

I claim 1. An ellipsograph comprising a frame having supporting legs and crossed diametral slots, blocks slidable in the slots and having portions thereof projecting above and below the frame, a rod detachably connected to the upperportion of the blocks and extending beyond the frame for drawing large ellipses, a rod detachably connected to the lower portions of the blocks, for drawing small ellipses within the legs of the frame and 21V scriber carried by said rods.

2. A device for drawing ellipses and circles comprising a frame having crossed diametral slots and supporting legs at the outer edges of said frame, a pair of blocks reversible and slidable in the slots and having portions thereof projecting above and below the frame, a long rod connected to the upper portions of the blocks and adjustable longitudinally therein for drawing ellipses beyond the supporting legs of the frame, a shorter rod longitudinally adjustable in the lower portions of said blocks for drawing smaller ellipses within said supporting legs, a swivelled cap at the upper end of one of the blocks for using the device in drawing circles, and means for connecting each pair of blocks together.

3. A device for drawing ellipses and circles comprising a circular frame having crossed diametral slots and supporting legs at the outer edges of said frame, a pair of and on which said blocks are adjustable longitudinally with respect to each other for drawing ellipses within said supporting legs, a swivelled cap at the outer end of one of the blocks for using the device in drawing circles, and means for connecting each pair of blocks to hold the block with the swivelled cap at the center of the frame; together with a block adjustable on one of the rods for traveling on the rim of the circular frame when the device is used in drawing circles.

ROBERT E. MANN.

blocks reversible and slidable in the slots and having portions thereof projecting above and below the frame, a long rod connected to the upper portions of the blocks and adjustable longitudinally therein for drawing ellipses beyond the supporting legs of the frame. and a shorter rod longitudinally adjustable in the lower portions of said blocks for drawirn smaller ellipses within said supporting legs, a swivelled cap at the upper end of one of the blocks for using the device in drawing circles, means for connecting each pair of blocks together, and a block adjustable on the rod in the upper portions of the blocks and having a bearing at the lower end thereof to travel around the circular rim of the frame for supporting said rod in drawing circles.

4. A device for drawing ellipses and circles comprising a circular frame having crossed diametral slots, legs pivotally secured to the outer edges of the frame for supporting the same above the work, a pair of blocks reversible and slidable in the slots and having portions thereof projecting above and below the frame, a long rod detachably connected to the upper portions of the blocks and on which said blocks are adjustable longitudinally with respect to each other for drawing 

